The biochemical mechanisms by which insulin exerts its biological effects are not known. We will examine the biochemical events associated with the stimulation by insulin of the active transport of sodium. We have recently demonstrated that insulin induces the synthesis of a cytoplasmic mRNA as well as the synthesis of cytoplasmic and plasma membrane proteins. We plan to translate the induced mRNA in vitro and compare the proteins with those made in vivo. Characterizing these insulin induced proteins and comparing them to proteins induced by aldosterone may clarify the role each plays in the regulation of sodium transport. We will attempt to characterize these induced proteins and determine whether or not they bind known inhibitors (ouabain, amiloride) of sodium transport. We will also attempt to compare the mechanism of the fast-acting peptide hormone vasopressin with that of insulin in stimulating sodium transport. These results should give insight into the hormonal regulation of sodium balance as well as electrolyte balance in the diabetic patient.